The ATHENA-OAWL Doppler Wind Lidar Mission

ATHENA-OAWL (Atmospheric Transport, Hurricanes, and Extra-Tropical Numerical Weather Prediction with the Optical Autocovariance Wind Lidar) is a mission proposed to NASA's Earth Venture ¨CInstrument program. The mission's overall goal is to utilize a Doppler wind lidar (DWL) implemented on the International Space Station (ISS) to help find a science path for next-generation global weather prediction and climate analysis. It will measure wind profiles at low and mid-latitudes, from the surface to 25 km in 1 km or better increments, more than doubling the number of profiles provided by current radiosonde networks, and with more uniform coverage including over the oceans. Both components of horizontal winds will be measured with ≤ 100 km along-track resolution and better than 3 m/s resolution when adequate aerosols are present. Beyond improvements in weather prediction, ATHENA-OAWL will improve our understanding of the interactions between aerosol radiative forcing and atmospheric dynamics and tropical cyclone genesis, as well as the impact of long range aerosol transport on energy and hydrologic cycles.

The proposed ATHENA-OAWL mission is enabled by the use of the ISS. The JEM-EF platform on ISS provides ample power and mass capability. The ISS utilizes a TDRSS downlink (when available) that provides near instantaneous downlink of wind measurements that can be quickly processed and disseminated to the user community for assimilation into numerical weather prediction models. A "design-to-cost" approach is used for the lidar and mission in order to fit within the cost cap of Earth Venture. A 532 nm DWL based on the Optical Autocovariance technique was chosen after modeling and OSSE results showed sufficient performance over a significant fraction of the atmosphere to have a positive impact on forecast skill. The instrument approach utilizes a field-widened Mach-Zender interferometer as its optical frequency discriminator in the lidar receiver, a direct detection technique. The presentation will focus on the mission design and the methodology used in developing the DWL to meet the objectives.